Wednesday 8 May 2011

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Tuesday 7 May 2011





Learning Intentions:

1. To become familiar with chromatography and be able to apply it to 'real life'

situations.

2. To perform 'fair tests' in Science identifying substances and fibres.

3. Identify and group fingerprintsinto 3 main categories: Arch, Loop

and Whorl.

4. Set up and carry out Scientific Experiments following the correct process

of; Aim, Equipment, Hypothesis, Method, Results and Conclusion.

5. Work collaboratively with peers to solve problems using the skills learnt.

Lesson One - Paper Chromatography

Chromatography is a technique used for seperating mixtures. In all of the variations of Chromatography, a substance is placed onto or into a medium and then a solvent passes through the test substance, some of the test substance may be attracted to the solven and follow it up in the medium. Different types of molecules are transported different distances, causing them to seperate. In these activities, filter paper is the medium, solvent is the solvent and black ink is the test substance. Chromatography is used in crime labs to seperate the components of 'clue' substances such as blood, ink or other mixtures found at the scene of a crime. Chromatograms of these clue substances are then compared with those of the suspected sources.

Chromatography Monday 9th May 2011

L.I I am learning the process of the chromatography and use this

to assist with solving the crime.

Aim: To use chromatography to distinguish which pen was used in the ransom note.

Hypothesis: I think that the Black marker will be the one the crimanal used because on the sheet it looks like it has run out abit and the black marker is a bad brand.

Black marker x5

Casade marker x14

Sharpie x3

Vivid x4

Equipment - Beaker, felt pens, ransom note, filter paper, water, hand lens, masking tape and straws.

Method:

1. Gather samples of pens.

2. Draw a line across a strip of filter paper, 1-4cm from the bottom.

3. Attach to straw with masking tape.

4. Put filter paper in beaker, making sure the ink is at least 1-2cm above

the water.

5. Observe.

6. Remove filter when water has travelled about 3/4 of the way up the strip.

7. Compare results with the ransom note results.

Results -

1. Black Ballpoint Pen

2. Vivid

3. Cascade marker

4. Sharpie

5. Black marker

Reflection - I have learnt how the CSI crew find out what brand of pen was used and how to use iodine and paper strip thingys.


Lesson Three - Kitchen Chaos Wednesday 11 May 2011:

The kitchen cupboard has got very damp and the labels have fallen off some

of the containers. From the label scraps it is found that there is:

Icing sugar

baking soda

salt

cream of tartar

cornflour

TASK - Make order out of chaos

Use a series of simple tests and good observations to find out what substance is in

each container.

Caution: You are not allowed to taste them! Please use small quantities.

Aim: to find out what the substance is by carrying out a series of simple tests.

Hypothesis:

I think that the substance in the different containers is;

Substance A - Cream Of Tarta

Substance B - Salt

Substance C - Corn Flower

Substance D - Icing sugar

Substance E - Baking Soda

Equipment - Five containers with the different substances labelled A, B, C, D, E.

- Eyedroppers

- Vinegar

- Magnifying Glass

- Litmus Paper (red and blue)

- Iodine

CLUES TO HELP YOU.......................

1. Cream of tartar is an acid, and turns blue litmus paper red.

2. Cornflour and sugar are neutral and don't affect litmus paper.

3. Salt and bicarbonate of soda are alkaline, that is they turn red litmus paper blue

4. Bicarbonate of soda fizzes when mixed with vinegar.

5. Iodine changes from yellow-brown to blue-black with cornflour.

There are many different ways of telling the differences between substances.

You could:

  • Smell them carefully.

  • Compare the way they dissolve in water.

  • Examine with a magnifying glass.

  • Test the acidity with litmus paper.

  • Test the reaction with vinegar and iodine.

Results:

Substance A is Corn flower Substance B is Salt

Substance C is Baking Soda Substance D is Icing Sugar

Substance E is Cream of Tarta


Lesson 3 - Fossicking for Fuels Friday 13 April 2011:

Aim: to determine properties of different fibres/materials.

(Record your results on the sheet provided then glue this into your Science book.)

Equipment:

1. 3 different types of material.

2. 2 beakers

3. 3 test tubes

4. Force meter (spring balance)

5. Ruler

6. Felt pen

7. Magnifying glass

8. Tongs

9. Candle

THE TESTS

TASK ONE - HOW MANY FIBRES ARE THERE IN THE MATERIAL?

Wool:100

Cotton:80
Polyester:80

TASK TWO - WHICH MATERIAL IS THE STRONGEST?

Wool:4

Cotton:5
Polyester:2

TASK THREE - WHICH FIBRES SOAK UP THE MOST WATER?

Wool:2cm

Cotton:2cm
Polyester:3cm

TASK FOUR - HOW DO THE MATERIALS BURN?

TASK FIVE - WHICH MATERIALS STRETCH THE MOST?

(Record results on the sheet provided)



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Lesson 5 - Hair Analysis Friday 20 May 2011: Learning Intention: We are learning to 1. think about the process involved in developing a technique for forensic analysis 2. identify the physical structures of hair 3. use our observational skills, critical thinking and microscopy Background information Unfortunately hair is not the best type of physical evidence for establishing identity. It is not possible to show with any certainty that two hairs came from the same person or animal. However hair can be used to rule out certain suspects or scenarios. It can also be used to corroborate (support) other physical evidence if it is consistent with the rest of the evidence. Guide to Identification Cuticle - Outer coating composed of overlapping scales
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Medulla - Central core, this may be absent
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Cortex - Protein rich structure surrounding the medulla; contains pigment
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